Packing



July 31 '1951 w. M. DE wrrr, sR 2,562,262

PACKING Filed Jan. 26, 1946 zl'flyzl d l Il .la

ll Il gan "mln Il v. v n

"Parental July 31, `1951 UNITED STATES PATNT\QFF|CE Walter M. De Witt,Sr., Somerville, N. J., assignor to Johns-Manville Corporation, NewYork, N. Y., a corporation of New York Application January 26, 1946,Serial No. 643,717

3 Claims. (Cl. 288-72) l The present invention relates to improvedpackings and, more particularly, to improvements in packings embodyinga, knitted, metal mesh or fabric as a major constituent.

Heretofore packings have been made comprising one or more cords formedof resilient, knitted, corrosion-resistant, metal fabric .composed ofrelatively thin, flat, narrow, metal ribbons. The knitted metal mesh,suitably of tubular form, is compacted into a cord, preferably bytwisting, and a plurality of the cords are braided or otherwiseassembled together to form the packing. The packing preferably containsa sealing media which may be of different types, depending upon thepurpose for which the packing is to be employed. For example, in certainapplications where high temperatures are encountered, such sealing mediahas taken the form of a brous core strand around which the metal mesh istwisted or otherwise compacted, the core strand, preferably an asbestoswicking or roving, sealing the mesh of the fabric.

The instant invention has for its principal object the provision of apacking for high temperature uses, for example, as an expansion jointpacking for locomotives and the like, the packing embodying an improvedform and arrangement of sealing'media.

Fig. 3 is a diagrammatic view on an enlarged scale showing a section ofthe metal mesh and the sealing material thereon, and n Fig. 4 is adiagrammatic view illustrating a cord formed of the metal mesh fabric.

Referring now to the drawings, there is shown a packing I0 embodying theinvention and formed of a plurality of inter-related cords I 2 formedprimarily of a knitted, corrosion-resistant, metal mesh fabric. Theseveral cords I2 are interrelated or associated together preferably withadditional stuifer cords, such as reinforcing core I I and cornerreinforcing cords I5. The core and corner cords comprise a number ofasbestos yarns suitably wire reinforced in a conventional manner andtwisted together into cord form. The wire reinforcement may be of thesame metal used for the knitted mesh. The packingl is fabricatedpreferably by a braiding operation, as illustrated, and the braid ismolded or compressed Another object of the inventionis the provision ofa packing including inter-related or interbraided cordsof compactedmetal mesh, the cords carrying a sealing material, particularly loosefibers, distributed over, and preferably adhered to, the mesh. Theknitted mesh may be twisted or otherwise compacted around a reinforcingcore consisting, forA example, of a number of asbestos strands twistedtogether into a cord. 'I'he packing also preferably contains stuffercords or strands of similar composition to such cores. The inventionprovides a packing which is capable of long wear but which, at the sametime, provides an efficient seal against leakage under conditions ofhigh temperature and pressure.

My invention will be more fully understood and `further objects andadvantages thereof `will become apparent when reference is made tov themore detailed description of a preferred embodiinto the desiredcross-sectional conguration of the completed packing.

Cords I2, illustrated particularly in Figs. 2, 3 and 4,' comprise stripsof metal mesh fabric I6 knitted from thin, flat, narrow, metallicstrands of, preferably, a corrosion-resistant, metal or metal alloy,such as copper, aluminum or nickel steel. In certain instances a softermetal or metal alloy may be employed, such as lead, babbitt or the like,but where a relatively high degree of resilience is desired as isgenerally the case, the harder metals are particularlyvapplicable. Apreferred material for the uses referred to above is copper, althoughalloys such as Inconel or Monel metal may be used. The individual, at,metal strands are fabricated into mesh on knitting equipment of anysuitable type such, for example, as a circular knitting machine, toprovide a continuous, tubular fabric, as shown in Fig. 2.

The knitted metal mesh carries a distributed, brous sealing material I8,particularly loose asbestos fiber, in such quantities that when the meshis compacted as by twisting, the fibers form a barrier to the passage ofgases or other fluids through the compacted cord without, however,destroying the resilient characteristics of the cord. AFibrous sealingmaterial I8 is suitably initially adhered to the metal mesh by a tackyadhesive as, for example, a rubber cement or the like.

In the preferred embodiment each cord I2 contains a core 20 comprising aplurality ofl strands of wire reinforced asbestos yarn, suitably ofsimilar type to that employed for cords 3 Il and I5. 'I'he strands aretwisted together to form the core 20 and the knitted mesh is twistedaround the core, preferably in a direction opposite that of the twist ofthe core. The core serves as a reinforcing and stretch limiting elementfor the mesh cords.

In the manufacture of a packing in accordance with the invention, theknitted mesh, preferably of tubular form as previously pointed out, isflattened and fed from a supply thereof through a bath of a suitableadhesive or tacky substance, preferably of the type of rubber cement,for example, a butyl rubber cut back in gasoline or other solvent. Afterdraining and drying, the mesh has loose asbestos fiber depositedthereon, the fiber preferably being intermixed with powdered graphite inproportions, say, 15.63%4

asbestos ber and 37% powdered graphite. The fibers and graphite areretained by the tacky adhesive. The tubularmsh with the distributedfiber is then fed' through a. condensing die and to a twisting device ofany conventional construction, whereby the fabric "is compacted ortwisted into cord form. Stufl'er cords I4 and I5 and core 20 arepreferably coated with graphite. The cords are first treated with alubricant, preferably a lubricating oil in which there is a smallpercentage of butyl rubber. In addition to its lubricating function theoil serves as an adhesive to retain the powdered graphite. Core 20 isfed to the iiattened, tubular fabric prior to the twisting operation, asindicated in Fig. 4, and passes therewith through the twister toconstitute a 4 Having thus described my invention in rather full detailit will be understood that these details need not be strictly adhered tobut that various changes and modifications may suggest them- 5 selves toone skilled in the art, all falling within the scope of the invention asdefined by the subjoined claims.

What I claim is:

1. A packing comprising a plurality of interrelated, twisted cordsformed of resilient fabric the fabric.

2. A packing comprising a plurality of interrelated, twisted cordsformed of resilient fabric knitted from metal strands, said fabrichaving asbestos fibers distributed thereover, and the fabric thereaftertwisted into the cord form to intimately bind the fibers into the meshof the fabric and lock them against displacement between inter-engagingstrands of the fabric.

3. A packing comprising a plurality of interrelated, twisted cordsformed of resilient fabric knitted from metal strands. said fabrichaving asbestos bers distributed thereover and adhered thereto, and thefabric thereafter twisted into REFERENCES CITED The following referencesare of record in the ille of this patent:

achieve the desired packing shape as, for ex- UNITED STATES PATENTScumming et al. Apr. 9. 1949 l5 the mesh'of thefabric andlock themagainst l /disp'lacement between inter-engaging strands of Certificateof Correction Patent No. 2,562,262 July 31, 1951 WALTER M. DE WITT, SR.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows:

Column 3, line 48, after mesh and before the comma insert bef/veenatea-engaging strands of the fabric;

and that the said Letters Patent should be read as corrected above, sothat the same may conform to the record of the case in the Patent O'Hoe.

Signed and sealed this 9th day of October, A. D. 1951.

[SEAL] THOMAS F. MURPHY, A

Assistant Commissioner 0f Patents.

